Putting the instruction layout in a table.

Author: nating

README.md

@@ -31,9 +31,10 @@ Each of these instructions has one or more _micro-operations_ in _Control Memory
   LDR and SR make use of the _temporary register_, Register 8. And take more than one micro-operation to execute. These, as well as the branching operations can take more than one clock-cycle to be performed.  
 
 An instruction in memory has:
-* An Opcode
-* A Destination Register
-* Two source Registers
+
+Opcode    | Destination Register | Source Register A | Source Register B
+----------|---------------------------------------------------------------------------------------------
+ 7 bits   | 3 bits               | 3 bits            | 3 bits
 
 The _opcode_ of an instruction is the address in Control Memory of the first micro-operation for that instruction. The opcode is put into the _Control Address Register_, which indexes the micro-operation. The opcode is 7 bits long. The registers (DR,SA & SB) specified in the instruction are 3 bits each and index the _Register File_. There are 8 registers in the Register File. Registers 0 through 7 can be specified as the source or destination registers for instructions, whereas register 8 is used for certain less straight forward instructions that need the use of another.